Wash and pick over beans. Cover with water and soak overnight (or boil for 10 minutes and let sit for an hour).
Discard soaking water, rinse beans and put in a large soup pot. Add the 8 cups of water and bring to a boil. Cover tightly and reduce heat to a low simmer. Add carrots.
In a non-stick pan saute onion in balsamic vinegar until it carmelizes (this takes a while on low heat). Add garlic, celery leaves, and bell pepper. Continue sauteing, adding more liquid as necessary. When the mixture has cooked down somewhat, add it to the beans.
Add the remaining ingredients except the miso. Simmer *very* slowly for 2 hours, stirring occasionally. Stir in the miso and simmer from 1 to 2 more hours (depending on when you're ready to eat and if you can resist the aroma). Remove bay leaves and serve with hard vegan bread and a salad.